File size: 33,578 Bytes
1bb1365
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
# Copyright (C) 2022-present Naver Corporation. All rights reserved.
# Licensed under CC BY-NC-SA 4.0 (non-commercial use only).

# --------------------------------------------------------
# Dataset structure for flow
# --------------------------------------------------------

import json
import os
import os.path as osp
import pickle
import struct
from copy import deepcopy

import h5py
import numpy as np
import torch
from PIL import Image
from torch.utils import data

from .augmentor import FlowAugmentor
from .datasets_stereo import _read_img, _read_pfm, dataset_to_root, img_to_tensor

dataset_to_root = deepcopy(dataset_to_root)

dataset_to_root.update(
    **{
        "TartanAir": "./data/stereoflow/TartanAir",
        "FlyingChairs": "./data/stereoflow/FlyingChairs/",
        "FlyingThings": osp.join(dataset_to_root["SceneFlow"], "FlyingThings") + "/",
        "MPISintel": "./data/stereoflow//MPI-Sintel/" + "/",
    }
)
cache_dir = "./data/stereoflow/datasets_flow_cache/"


def flow_to_tensor(disp):
    return torch.from_numpy(disp).float().permute(2, 0, 1)


class FlowDataset(data.Dataset):
    def __init__(self, split, augmentor=False, crop_size=None, totensor=True):
        self.split = split
        if not augmentor:
            assert crop_size is None
        if crop_size is not None:
            assert augmentor
        self.crop_size = crop_size
        self.augmentor_str = augmentor
        self.augmentor = FlowAugmentor(crop_size) if augmentor else None
        self.totensor = totensor
        self.rmul = 1  # keep track of rmul
        self.has_constant_resolution = True  # whether the dataset has constant resolution or not (=> don't use batch_size>1 at test time)
        self._prepare_data()
        self._load_or_build_cache()

    def prepare_data(self):
        """
        to be defined for each dataset
        """
        raise NotImplementedError

    def __len__(self):
        return len(
            self.pairnames
        )  # each pairname is typically of the form (str, int1, int2)

    def __getitem__(self, index):
        pairname = self.pairnames[index]

        # get filenames
        img1name = self.pairname_to_img1name(pairname)
        img2name = self.pairname_to_img2name(pairname)
        flowname = (
            self.pairname_to_flowname(pairname)
            if self.pairname_to_flowname is not None
            else None
        )

        # load images and disparities
        img1 = _read_img(img1name)
        img2 = _read_img(img2name)
        flow = self.load_flow(flowname) if flowname is not None else None

        # apply augmentations
        if self.augmentor is not None:
            img1, img2, flow = self.augmentor(img1, img2, flow, self.name)

        if self.totensor:
            img1 = img_to_tensor(img1)
            img2 = img_to_tensor(img2)
            if flow is not None:
                flow = flow_to_tensor(flow)
            else:
                flow = torch.tensor(
                    []
                )  # to allow dataloader batching with default collate_gn
            pairname = str(
                pairname
            )  # transform potential tuple to str to be able to batch it

        return img1, img2, flow, pairname

    def __rmul__(self, v):
        self.rmul *= v
        self.pairnames = v * self.pairnames
        return self

    def __str__(self):
        return f"{self.__class__.__name__}_{self.split}"

    def __repr__(self):
        s = f"{self.__class__.__name__}(split={self.split}, augmentor={self.augmentor_str}, crop_size={str(self.crop_size)}, totensor={self.totensor})"
        if self.rmul == 1:
            s += f"\n\tnum pairs: {len(self.pairnames)}"
        else:
            s += f"\n\tnum pairs: {len(self.pairnames)} ({len(self.pairnames)//self.rmul}x{self.rmul})"
        return s

    def _set_root(self):
        self.root = dataset_to_root[self.name]
        assert os.path.isdir(
            self.root
        ), f"could not find root directory for dataset {self.name}: {self.root}"

    def _load_or_build_cache(self):
        cache_file = osp.join(cache_dir, self.name + ".pkl")
        if osp.isfile(cache_file):
            with open(cache_file, "rb") as fid:
                self.pairnames = pickle.load(fid)[self.split]
        else:
            tosave = self._build_cache()
            os.makedirs(cache_dir, exist_ok=True)
            with open(cache_file, "wb") as fid:
                pickle.dump(tosave, fid)
            self.pairnames = tosave[self.split]


class TartanAirDataset(FlowDataset):
    def _prepare_data(self):
        self.name = "TartanAir"
        self._set_root()
        assert self.split in ["train"]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root, pairname[0], "image_left/{:06d}_left.png".format(pairname[1])
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root, pairname[0], "image_left/{:06d}_left.png".format(pairname[2])
        )
        self.pairname_to_flowname = lambda pairname: osp.join(
            self.root,
            pairname[0],
            "flow/{:06d}_{:06d}_flow.npy".format(pairname[1], pairname[2]),
        )
        self.pairname_to_str = lambda pairname: os.path.join(
            pairname[0][pairname[0].find("/") + 1 :],
            "{:06d}_{:06d}".format(pairname[1], pairname[2]),
        )
        self.load_flow = _read_numpy_flow

    def _build_cache(self):
        seqs = sorted(os.listdir(self.root))
        pairs = [
            (osp.join(s, s, difficulty, Pxxx), int(a[:6]), int(a[:6]) + 1)
            for s in seqs
            for difficulty in ["Easy", "Hard"]
            for Pxxx in sorted(os.listdir(osp.join(self.root, s, s, difficulty)))
            for a in sorted(
                os.listdir(osp.join(self.root, s, s, difficulty, Pxxx, "image_left/"))
            )[:-1]
        ]
        assert len(pairs) == 306268, "incorrect parsing of pairs in TartanAir"
        tosave = {"train": pairs}
        return tosave


class FlyingChairsDataset(FlowDataset):
    def _prepare_data(self):
        self.name = "FlyingChairs"
        self._set_root()
        assert self.split in ["train", "val"]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root, "data", pairname + "_img1.ppm"
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root, "data", pairname + "_img2.ppm"
        )
        self.pairname_to_flowname = lambda pairname: osp.join(
            self.root, "data", pairname + "_flow.flo"
        )
        self.pairname_to_str = lambda pairname: pairname
        self.load_flow = _read_flo_file

    def _build_cache(self):
        split_file = osp.join(self.root, "chairs_split.txt")
        split_list = np.loadtxt(split_file, dtype=np.int32)
        trainpairs = ["{:05d}".format(i) for i in np.where(split_list == 1)[0] + 1]
        valpairs = ["{:05d}".format(i) for i in np.where(split_list == 2)[0] + 1]
        assert (
            len(trainpairs) == 22232 and len(valpairs) == 640
        ), "incorrect parsing of pairs in MPI-Sintel"
        tosave = {"train": trainpairs, "val": valpairs}
        return tosave


class FlyingThingsDataset(FlowDataset):
    def _prepare_data(self):
        self.name = "FlyingThings"
        self._set_root()
        assert self.split in [
            f"{set_}_{pass_}pass{camstr}"
            for set_ in ["train", "test", "test1024"]
            for camstr in ["", "_rightcam"]
            for pass_ in ["clean", "final", "all"]
        ]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root,
            f"frames_{pairname[3]}pass",
            pairname[0].replace("into_future", "").replace("into_past", ""),
            "{:04d}.png".format(pairname[1]),
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root,
            f"frames_{pairname[3]}pass",
            pairname[0].replace("into_future", "").replace("into_past", ""),
            "{:04d}.png".format(pairname[2]),
        )
        self.pairname_to_flowname = lambda pairname: osp.join(
            self.root,
            "optical_flow",
            pairname[0],
            "OpticalFlowInto{f:s}_{i:04d}_{c:s}.pfm".format(
                f="Future" if "future" in pairname[0] else "Past",
                i=pairname[1],
                c="L" if "left" in pairname[0] else "R",
            ),
        )
        self.pairname_to_str = lambda pairname: os.path.join(
            pairname[3] + "pass",
            pairname[0],
            "Into{f:s}_{i:04d}_{c:s}".format(
                f="Future" if "future" in pairname[0] else "Past",
                i=pairname[1],
                c="L" if "left" in pairname[0] else "R",
            ),
        )
        self.load_flow = _read_pfm_flow

    def _build_cache(self):
        tosave = {}
        # train and test splits for the different passes
        for set_ in ["train", "test"]:
            sroot = osp.join(self.root, "optical_flow", set_.upper())
            fname_to_i = lambda f: int(
                f[len("OpticalFlowIntoFuture_") : -len("_L.pfm")]
            )
            pp = [
                (osp.join(set_.upper(), d, s, "into_future/left"), fname_to_i(fname))
                for d in sorted(os.listdir(sroot))
                for s in sorted(os.listdir(osp.join(sroot, d)))
                for fname in sorted(
                    os.listdir(osp.join(sroot, d, s, "into_future/left"))
                )[:-1]
            ]
            pairs = [(a, i, i + 1) for a, i in pp]
            pairs += [(a.replace("into_future", "into_past"), i + 1, i) for a, i in pp]
            assert (
                len(pairs) == {"train": 40302, "test": 7866}[set_]
            ), "incorrect parsing of pairs Flying Things"
            for cam in ["left", "right"]:
                camstr = "" if cam == "left" else f"_{cam}cam"
                for pass_ in ["final", "clean"]:
                    tosave[f"{set_}_{pass_}pass{camstr}"] = [
                        (a.replace("left", cam), i, j, pass_) for a, i, j in pairs
                    ]
                tosave[f"{set_}_allpass{camstr}"] = (
                    tosave[f"{set_}_cleanpass{camstr}"]
                    + tosave[f"{set_}_finalpass{camstr}"]
                )
        # test1024: this is the same split as unimatch 'validation' split
        # see https://github.com/autonomousvision/unimatch/blob/master/dataloader/flow/datasets.py#L229
        test1024_nsamples = 1024
        alltest_nsamples = len(tosave["test_cleanpass"])  # 7866
        stride = alltest_nsamples // test1024_nsamples
        remove = alltest_nsamples % test1024_nsamples
        for cam in ["left", "right"]:
            camstr = "" if cam == "left" else f"_{cam}cam"
            for pass_ in ["final", "clean"]:
                tosave[f"test1024_{pass_}pass{camstr}"] = sorted(
                    tosave[f"test_{pass_}pass{camstr}"]
                )[:-remove][
                    ::stride
                ]  # warning, it was not sorted before
            assert (
                len(tosave["test1024_cleanpass"]) == 1024
            ), "incorrect parsing of pairs in Flying Things"
            tosave[f"test1024_allpass{camstr}"] = (
                tosave[f"test1024_cleanpass{camstr}"]
                + tosave[f"test1024_finalpass{camstr}"]
            )
        return tosave


class MPISintelDataset(FlowDataset):
    def _prepare_data(self):
        self.name = "MPISintel"
        self._set_root()
        assert self.split in [
            s + "_" + p
            for s in ["train", "test", "subval", "subtrain"]
            for p in ["cleanpass", "finalpass", "allpass"]
        ]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root, pairname[0], "frame_{:04d}.png".format(pairname[1])
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root, pairname[0], "frame_{:04d}.png".format(pairname[1] + 1)
        )
        self.pairname_to_flowname = (
            lambda pairname: None
            if pairname[0].startswith("test/")
            else osp.join(
                self.root,
                pairname[0].replace("/clean/", "/flow/").replace("/final/", "/flow/"),
                "frame_{:04d}.flo".format(pairname[1]),
            )
        )
        self.pairname_to_str = lambda pairname: osp.join(
            pairname[0], "frame_{:04d}".format(pairname[1])
        )
        self.load_flow = _read_flo_file

    def _build_cache(self):
        trainseqs = sorted(os.listdir(self.root + "training/clean"))
        trainpairs = [
            (osp.join("training/clean", s), i)
            for s in trainseqs
            for i in range(1, len(os.listdir(self.root + "training/clean/" + s)))
        ]
        subvalseqs = ["temple_2", "temple_3"]
        subtrainseqs = [s for s in trainseqs if s not in subvalseqs]
        subvalpairs = [(p, i) for p, i in trainpairs if any(s in p for s in subvalseqs)]
        subtrainpairs = [
            (p, i) for p, i in trainpairs if any(s in p for s in subtrainseqs)
        ]
        testseqs = sorted(os.listdir(self.root + "test/clean"))
        testpairs = [
            (osp.join("test/clean", s), i)
            for s in testseqs
            for i in range(1, len(os.listdir(self.root + "test/clean/" + s)))
        ]
        assert (
            len(trainpairs) == 1041
            and len(testpairs) == 552
            and len(subvalpairs) == 98
            and len(subtrainpairs) == 943
        ), "incorrect parsing of pairs in MPI-Sintel"
        tosave = {}
        tosave["train_cleanpass"] = trainpairs
        tosave["test_cleanpass"] = testpairs
        tosave["subval_cleanpass"] = subvalpairs
        tosave["subtrain_cleanpass"] = subtrainpairs
        for t in ["train", "test", "subval", "subtrain"]:
            tosave[t + "_finalpass"] = [
                (p.replace("/clean/", "/final/"), i)
                for p, i in tosave[t + "_cleanpass"]
            ]
            tosave[t + "_allpass"] = tosave[t + "_cleanpass"] + tosave[t + "_finalpass"]
        return tosave

    def submission_save_pairname(self, pairname, prediction, outdir, _time):
        assert prediction.shape[2] == 2
        outfile = os.path.join(
            outdir, "submission", self.pairname_to_str(pairname) + ".flo"
        )
        os.makedirs(os.path.dirname(outfile), exist_ok=True)
        writeFlowFile(prediction, outfile)

    def finalize_submission(self, outdir):
        assert self.split == "test_allpass"
        bundle_exe = "/nfs/data/ffs-3d/datasets/StereoFlow/MPI-Sintel/bundler/linux-x64/bundler"  # eg <bundle_exe> <path_to_results_for_clean> <path_to_results_for_final> <output/bundled.lzma>
        if os.path.isfile(bundle_exe):
            cmd = f'{bundle_exe} "{outdir}/submission/test/clean/" "{outdir}/submission/test/final" "{outdir}/submission/bundled.lzma"'
            print(cmd)
            os.system(cmd)
            print(f'Done. Submission file at: "{outdir}/submission/bundled.lzma"')
        else:
            print("Could not find bundler executable for submission.")
            print("Please download it and run:")
            print(
                f'<bundle_exe> "{outdir}/submission/test/clean/" "{outdir}/submission/test/final" "{outdir}/submission/bundled.lzma"'
            )


class SpringDataset(FlowDataset):
    def _prepare_data(self):
        self.name = "Spring"
        self._set_root()
        assert self.split in ["train", "test", "subtrain", "subval"]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root,
            pairname[0],
            pairname[1],
            "frame_" + pairname[3],
            "frame_{:s}_{:04d}.png".format(pairname[3], pairname[4]),
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root,
            pairname[0],
            pairname[1],
            "frame_" + pairname[3],
            "frame_{:s}_{:04d}.png".format(
                pairname[3], pairname[4] + (1 if pairname[2] == "FW" else -1)
            ),
        )
        self.pairname_to_flowname = (
            lambda pairname: None
            if pairname[0] == "test"
            else osp.join(
                self.root,
                pairname[0],
                pairname[1],
                f"flow_{pairname[2]}_{pairname[3]}",
                f"flow_{pairname[2]}_{pairname[3]}_{pairname[4]:04d}.flo5",
            )
        )
        self.pairname_to_str = lambda pairname: osp.join(
            pairname[0],
            pairname[1],
            f"flow_{pairname[2]}_{pairname[3]}",
            f"flow_{pairname[2]}_{pairname[3]}_{pairname[4]:04d}",
        )
        self.load_flow = _read_hdf5_flow

    def _build_cache(self):
        # train
        trainseqs = sorted(os.listdir(osp.join(self.root, "train")))
        trainpairs = []
        for leftright in ["left", "right"]:
            for fwbw in ["FW", "BW"]:
                trainpairs += [
                    (
                        "train",
                        s,
                        fwbw,
                        leftright,
                        int(f[len(f"flow_{fwbw}_{leftright}_") : -len(".flo5")]),
                    )
                    for s in trainseqs
                    for f in sorted(
                        os.listdir(
                            osp.join(self.root, "train", s, f"flow_{fwbw}_{leftright}")
                        )
                    )
                ]
        # test
        testseqs = sorted(os.listdir(osp.join(self.root, "test")))
        testpairs = []
        for leftright in ["left", "right"]:
            testpairs += [
                (
                    "test",
                    s,
                    "FW",
                    leftright,
                    int(f[len(f"frame_{leftright}_") : -len(".png")]),
                )
                for s in testseqs
                for f in sorted(
                    os.listdir(osp.join(self.root, "test", s, f"frame_{leftright}"))
                )[:-1]
            ]
            testpairs += [
                (
                    "test",
                    s,
                    "BW",
                    leftright,
                    int(f[len(f"frame_{leftright}_") : -len(".png")]) + 1,
                )
                for s in testseqs
                for f in sorted(
                    os.listdir(osp.join(self.root, "test", s, f"frame_{leftright}"))
                )[:-1]
            ]
        # subtrain / subval
        subtrainpairs = [p for p in trainpairs if p[1] != "0041"]
        subvalpairs = [p for p in trainpairs if p[1] == "0041"]
        assert (
            len(trainpairs) == 19852
            and len(testpairs) == 3960
            and len(subtrainpairs) == 19472
            and len(subvalpairs) == 380
        ), "incorrect parsing of pairs in Spring"
        tosave = {
            "train": trainpairs,
            "test": testpairs,
            "subtrain": subtrainpairs,
            "subval": subvalpairs,
        }
        return tosave

    def submission_save_pairname(self, pairname, prediction, outdir, time):
        assert prediction.ndim == 3
        assert prediction.shape[2] == 2
        assert prediction.dtype == np.float32
        outfile = osp.join(
            outdir,
            pairname[0],
            pairname[1],
            f"flow_{pairname[2]}_{pairname[3]}",
            f"flow_{pairname[2]}_{pairname[3]}_{pairname[4]:04d}.flo5",
        )
        os.makedirs(os.path.dirname(outfile), exist_ok=True)
        writeFlo5File(prediction, outfile)

    def finalize_submission(self, outdir):
        assert self.split == "test"
        exe = "{self.root}/flow_subsampling"
        if os.path.isfile(exe):
            cmd = f'cd "{outdir}/test"; {exe} .'
            print(cmd)
            os.system(cmd)
            print(f"Done. Submission file at {outdir}/test/flow_submission.hdf5")
        else:
            print("Could not find flow_subsampling executable for submission.")
            print("Please download it and run:")
            print(f'cd "{outdir}/test"; <flow_subsampling_exe> .')


class Kitti12Dataset(FlowDataset):
    def _prepare_data(self):
        self.name = "Kitti12"
        self._set_root()
        assert self.split in ["train", "test"]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root, pairname + "_10.png"
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root, pairname + "_11.png"
        )
        self.pairname_to_flowname = (
            None
            if self.split == "test"
            else lambda pairname: osp.join(
                self.root, pairname.replace("/colored_0/", "/flow_occ/") + "_10.png"
            )
        )
        self.pairname_to_str = lambda pairname: pairname.replace("/colored_0/", "/")
        self.load_flow = _read_kitti_flow

    def _build_cache(self):
        trainseqs = ["training/colored_0/%06d" % (i) for i in range(194)]
        testseqs = ["testing/colored_0/%06d" % (i) for i in range(195)]
        assert (
            len(trainseqs) == 194 and len(testseqs) == 195
        ), "incorrect parsing of pairs in Kitti12"
        tosave = {"train": trainseqs, "test": testseqs}
        return tosave

    def submission_save_pairname(self, pairname, prediction, outdir, time):
        assert prediction.ndim == 3
        assert prediction.shape[2] == 2
        outfile = os.path.join(outdir, pairname.split("/")[-1] + "_10.png")
        os.makedirs(os.path.dirname(outfile), exist_ok=True)
        writeFlowKitti(outfile, prediction)

    def finalize_submission(self, outdir):
        assert self.split == "test"
        cmd = f'cd {outdir}/; zip -r "kitti12_flow_results.zip" .'
        print(cmd)
        os.system(cmd)
        print(f"Done. Submission file at {outdir}/kitti12_flow_results.zip")


class Kitti15Dataset(FlowDataset):
    def _prepare_data(self):
        self.name = "Kitti15"
        self._set_root()
        assert self.split in ["train", "subtrain", "subval", "test"]
        self.pairname_to_img1name = lambda pairname: osp.join(
            self.root, pairname + "_10.png"
        )
        self.pairname_to_img2name = lambda pairname: osp.join(
            self.root, pairname + "_11.png"
        )
        self.pairname_to_flowname = (
            None
            if self.split == "test"
            else lambda pairname: osp.join(
                self.root, pairname.replace("/image_2/", "/flow_occ/") + "_10.png"
            )
        )
        self.pairname_to_str = lambda pairname: pairname.replace("/image_2/", "/")
        self.load_flow = _read_kitti_flow

    def _build_cache(self):
        trainseqs = ["training/image_2/%06d" % (i) for i in range(200)]
        subtrainseqs = trainseqs[:-10]
        subvalseqs = trainseqs[-10:]
        testseqs = ["testing/image_2/%06d" % (i) for i in range(200)]
        assert (
            len(trainseqs) == 200
            and len(subtrainseqs) == 190
            and len(subvalseqs) == 10
            and len(testseqs) == 200
        ), "incorrect parsing of pairs in Kitti15"
        tosave = {
            "train": trainseqs,
            "subtrain": subtrainseqs,
            "subval": subvalseqs,
            "test": testseqs,
        }
        return tosave

    def submission_save_pairname(self, pairname, prediction, outdir, time):
        assert prediction.ndim == 3
        assert prediction.shape[2] == 2
        outfile = os.path.join(outdir, "flow", pairname.split("/")[-1] + "_10.png")
        os.makedirs(os.path.dirname(outfile), exist_ok=True)
        writeFlowKitti(outfile, prediction)

    def finalize_submission(self, outdir):
        assert self.split == "test"
        cmd = f'cd {outdir}/; zip -r "kitti15_flow_results.zip" flow'
        print(cmd)
        os.system(cmd)
        print(f"Done. Submission file at {outdir}/kitti15_flow_results.zip")


import cv2


def _read_numpy_flow(filename):
    return np.load(filename)


def _read_pfm_flow(filename):
    f, _ = _read_pfm(filename)
    assert np.all(f[:, :, 2] == 0.0)
    return np.ascontiguousarray(f[:, :, :2])


TAG_FLOAT = 202021.25  # tag to check the sanity of the file
TAG_STRING = "PIEH"  # string containing the tag
MIN_WIDTH = 1
MAX_WIDTH = 99999
MIN_HEIGHT = 1
MAX_HEIGHT = 99999


def readFlowFile(filename):
    """
    readFlowFile(<FILENAME>) reads a flow file <FILENAME> into a 2-band np.array.
    if <FILENAME> does not exist, an IOError is raised.
    if <FILENAME> does not finish by '.flo' or the tag, the width, the height or the file's size is illegal, an Expcetion is raised.
    ---- PARAMETERS ----
        filename: string containg the name of the file to read a flow
    ---- OUTPUTS ----
        a np.array of dimension (height x width x 2) containing the flow of type 'float32'
    """

    # check filename
    if not filename.endswith(".flo"):
        raise Exception(
            "readFlowFile({:s}): filename must finish with '.flo'".format(filename)
        )

    # open the file and read it
    with open(filename, "rb") as f:
        # check tag
        tag = struct.unpack("f", f.read(4))[0]
        if tag != TAG_FLOAT:
            raise Exception("flow_utils.readFlowFile({:s}): wrong tag".format(filename))
        # read dimension
        w, h = struct.unpack("ii", f.read(8))
        if w < MIN_WIDTH or w > MAX_WIDTH:
            raise Exception(
                "flow_utils.readFlowFile({:s}: illegal width {:d}".format(filename, w)
            )
        if h < MIN_HEIGHT or h > MAX_HEIGHT:
            raise Exception(
                "flow_utils.readFlowFile({:s}: illegal height {:d}".format(filename, h)
            )
        flow = np.fromfile(f, "float32")
        if not flow.shape == (h * w * 2,):
            raise Exception(
                "flow_utils.readFlowFile({:s}: illegal size of the file".format(
                    filename
                )
            )
        flow.shape = (h, w, 2)
        return flow


def writeFlowFile(flow, filename):
    """
    writeFlowFile(flow,<FILENAME>) write flow to the file <FILENAME>.
    if <FILENAME> does not exist, an IOError is raised.
    if <FILENAME> does not finish with '.flo' or the flow has not 2 bands, an Exception is raised.
    ---- PARAMETERS ----
        flow: np.array of dimension (height x width x 2) containing the flow to write
        filename: string containg the name of the file to write a flow
    """

    # check filename
    if not filename.endswith(".flo"):
        raise Exception(
            "flow_utils.writeFlowFile(<flow>,{:s}): filename must finish with '.flo'".format(
                filename
            )
        )

    if not flow.shape[2:] == (2,):
        raise Exception(
            "flow_utils.writeFlowFile(<flow>,{:s}): <flow> must have 2 bands".format(
                filename
            )
        )

    # open the file and write it
    with open(filename, "wb") as f:
        # write TAG
        f.write(TAG_STRING.encode("utf-8"))
        # write dimension
        f.write(struct.pack("ii", flow.shape[1], flow.shape[0]))
        # write the flow

        flow.astype(np.float32).tofile(f)


_read_flo_file = readFlowFile


def _read_kitti_flow(filename):
    flow = cv2.imread(filename, cv2.IMREAD_ANYDEPTH | cv2.IMREAD_COLOR)
    flow = flow[:, :, ::-1].astype(np.float32)
    valid = flow[:, :, 2] > 0
    flow = flow[:, :, :2]
    flow = (flow - 2**15) / 64.0
    flow[~valid, 0] = np.inf
    flow[~valid, 1] = np.inf
    return flow


_read_hd1k_flow = _read_kitti_flow


def writeFlowKitti(filename, uv):
    uv = 64.0 * uv + 2**15
    valid = np.ones([uv.shape[0], uv.shape[1], 1])
    uv = np.concatenate([uv, valid], axis=-1).astype(np.uint16)
    cv2.imwrite(filename, uv[..., ::-1])


def writeFlo5File(flow, filename):
    with h5py.File(filename, "w") as f:
        f.create_dataset("flow", data=flow, compression="gzip", compression_opts=5)


def _read_hdf5_flow(filename):
    flow = np.asarray(h5py.File(filename)["flow"])
    flow[np.isnan(flow)] = np.inf  # make invalid values as +inf
    return flow.astype(np.float32)


# flow visualization
RY = 15
YG = 6
GC = 4
CB = 11
BM = 13
MR = 6
UNKNOWN_THRESH = 1e9


def colorTest():
    """
    flow_utils.colorTest(): display an example of image showing the color encoding scheme
    """
    import matplotlib.pylab as plt

    truerange = 1
    h, w = 151, 151
    trange = truerange * 1.04
    s2 = round(h / 2)
    x, y = np.meshgrid(range(w), range(h))
    u = x * trange / s2 - trange
    v = y * trange / s2 - trange
    img = _computeColor(
        np.concatenate((u[:, :, np.newaxis], v[:, :, np.newaxis]), 2)
        / trange
        / np.sqrt(2)
    )
    plt.imshow(img)
    plt.axis("off")
    plt.axhline(round(h / 2), color="k")
    plt.axvline(round(w / 2), color="k")


def flowToColor(flow, maxflow=None, maxmaxflow=None, saturate=False):
    """
    flow_utils.flowToColor(flow): return a color code flow field, normalized based on the maximum l2-norm of the flow
    flow_utils.flowToColor(flow,maxflow): return a color code flow field, normalized by maxflow
    ---- PARAMETERS ----
        flow: flow to display of shape (height x width x 2)
        maxflow (default:None): if given, normalize the flow by its value, otherwise by the flow norm
        maxmaxflow (default:None): if given, normalize the flow by the max of its value and the flow norm
    ---- OUTPUT ----
        an np.array of shape (height x width x 3) of type uint8 containing a color code of the flow
    """
    h, w, n = flow.shape
    # check size of flow
    assert n == 2, "flow_utils.flowToColor(flow): flow must have 2 bands"
    # fix unknown flow
    unknown_idx = np.max(np.abs(flow), 2) > UNKNOWN_THRESH
    flow[unknown_idx] = 0.0
    # compute max flow if needed
    if maxflow is None:
        maxflow = flowMaxNorm(flow)
    if maxmaxflow is not None:
        maxflow = min(maxmaxflow, maxflow)
    # normalize flow
    eps = np.spacing(1)  # minimum positive float value to avoid division by 0
    # compute the flow
    img = _computeColor(flow / (maxflow + eps), saturate=saturate)
    # put black pixels in unknown location
    img[np.tile(unknown_idx[:, :, np.newaxis], [1, 1, 3])] = 0.0
    return img


def flowMaxNorm(flow):
    """
    flow_utils.flowMaxNorm(flow): return the maximum of the l2-norm of the given flow
    ---- PARAMETERS ----
        flow: the flow

    ---- OUTPUT ----
        a float containing the maximum of the l2-norm of the flow
    """
    return np.max(np.sqrt(np.sum(np.square(flow), 2)))


def _computeColor(flow, saturate=True):
    """
    flow_utils._computeColor(flow): compute color codes for the flow field flow

    ---- PARAMETERS ----
        flow: np.array of dimension (height x width x 2) containing the flow to display
    ---- OUTPUTS ----
        an np.array of dimension (height x width x 3) containing the color conversion of the flow
    """
    # set nan to 0
    nanidx = np.isnan(flow[:, :, 0])
    flow[nanidx] = 0.0

    # colorwheel
    ncols = RY + YG + GC + CB + BM + MR
    nchans = 3
    colorwheel = np.zeros((ncols, nchans), "uint8")
    col = 0
    # RY
    colorwheel[:RY, 0] = 255
    colorwheel[:RY, 1] = [(255 * i) // RY for i in range(RY)]
    col += RY
    # YG
    colorwheel[col : col + YG, 0] = [255 - (255 * i) // YG for i in range(YG)]
    colorwheel[col : col + YG, 1] = 255
    col += YG
    # GC
    colorwheel[col : col + GC, 1] = 255
    colorwheel[col : col + GC, 2] = [(255 * i) // GC for i in range(GC)]
    col += GC
    # CB
    colorwheel[col : col + CB, 1] = [255 - (255 * i) // CB for i in range(CB)]
    colorwheel[col : col + CB, 2] = 255
    col += CB
    # BM
    colorwheel[col : col + BM, 0] = [(255 * i) // BM for i in range(BM)]
    colorwheel[col : col + BM, 2] = 255
    col += BM
    # MR
    colorwheel[col : col + MR, 0] = 255
    colorwheel[col : col + MR, 2] = [255 - (255 * i) // MR for i in range(MR)]

    # compute utility variables
    rad = np.sqrt(np.sum(np.square(flow), 2))  # magnitude
    a = np.arctan2(-flow[:, :, 1], -flow[:, :, 0]) / np.pi  # angle
    fk = (a + 1) / 2 * (ncols - 1)  # map [-1,1] to [0,ncols-1]
    k0 = np.floor(fk).astype("int")
    k1 = k0 + 1
    k1[k1 == ncols] = 0
    f = fk - k0

    if not saturate:
        rad = np.minimum(rad, 1)

    # compute the image
    img = np.zeros((flow.shape[0], flow.shape[1], nchans), "uint8")
    for i in range(nchans):
        tmp = colorwheel[:, i].astype("float")
        col0 = tmp[k0] / 255
        col1 = tmp[k1] / 255
        col = (1 - f) * col0 + f * col1
        idx = rad <= 1
        col[idx] = 1 - rad[idx] * (1 - col[idx])  # increase saturation with radius
        col[~idx] *= 0.75  # out of range
        img[:, :, i] = (255 * col * (1 - nanidx.astype("float"))).astype("uint8")

    return img


# flow dataset getter


def get_train_dataset_flow(dataset_str, augmentor=True, crop_size=None):
    dataset_str = dataset_str.replace("(", "Dataset(")
    if augmentor:
        dataset_str = dataset_str.replace(")", ", augmentor=True)")
    if crop_size is not None:
        dataset_str = dataset_str.replace(
            ")", ", crop_size={:s})".format(str(crop_size))
        )
    return eval(dataset_str)


def get_test_datasets_flow(dataset_str):
    dataset_str = dataset_str.replace("(", "Dataset(")
    return [eval(s) for s in dataset_str.split("+")]